History of the basin

The systematic scientific studies of tropical systems in the Bay of Bengal and Arabian Sea was started during the 19th century by Henry Piddington.[6] Piddington utilised meteorological logs of vessels that navigated the seas and published a series of memoirs, in the “Journal of the Asiatic Society of Bengal” between 1839 and 1858.[6] These memoirs gave accounts and tracks of individual storms in the Bay of Bengal and the Arabian Sea.[6]

During the 2004 post monsoon season the IMD started to name tropical cyclones within the basin, with the first one named Cyclone Onil during September 2004.[7] During 2015 a modification to the intensity scale took place, with the IMD and WMO calling a system with 3-minute maximum sustained wind speeds between 90 knots (165km/h; 105mph) and 120 knots (220km/h; 140mph) an extremely severe cyclonic storm.[8]

Water temperatures in the Arabian Sea are typically warm enough to allow for tropical cyclogenesis year round, although strong wind shear from the monsoon trough prevents formation in the summer months and limits intensity other times of the year. An increase in air pollution since the 1930s caused a decrease in the wind shear, allowing storms to have become stronger since 1979.[9]

Notes

A study analyzing the spring season of tropical cyclones in the Bay of Bengal[13] found increases in both premonsoon precipitation and tropical cyclone intensity as a result of enhanced large-scale monsoon circulation after 1979. The deepened monsoon trough in the Bay of Bengal not only affects cyclone frequency and timing, but also acts to direct more cyclones towards Myanmar. Increased anthropogenic aerosols likely contributed to such a regional climate change.

Related Research Articles

The 1992 North Indian Ocean cyclone season was unofficially the most active year on record for the basin, with 10 tropical storms developing, according to the Joint Typhoon Warning Center (JTWC). There are two main seas in the North Indian Ocean – the Bay of Bengal to the east of the Indian subcontinent – and the Arabian Sea to the west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the JTWC releases unofficial advisories. An average of four to six storms form in the North Indian Ocean every season with peaks in May and November. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.

The 2006 North Indian Ocean cyclone season had no bounds, but cyclones tend to form between April and December, with peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.

The 2007 North Indian Ocean cyclone season was at the time, the most active North Indian Ocean cyclone season on record until surpassed in 2019. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.

The 2008 North Indian cyclone season was one of the most disastrous tropical cyclone seasons in modern history, with tropical cyclones leaving more than 140,000 people dead and causing more than US$14 billion in damage, making it the costliest season on record in the North Indian Ocean. The season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. There are two main seas in the North Indian Ocean—the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the Joint Typhoon Warning Center releases unofficial advisories. An average of four to six storms form in the North Indian Ocean every season with peaks in May and November. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.

The 1990 North Indian Ocean cyclone season featured a below average total of twelve cyclonic disturbances and one of the most intense tropical cyclones in the basin on record. During the season the systems were primarily monitored by the India Meteorological Department, while other warning centres such as the United States Joint Typhoon Warning Center also monitored the area. During the season, there were at least 1,577 deaths, while the systems caused over US$693 million in damages. The most significant system was the 1990 Andhra Pradesh cyclone, which was the most intense, damaging, and the deadliest system of the season.

The 1989 North Indian Ocean cyclone season was a below-average season in annual cycle of tropical cyclone formation. The season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. There are two main seas in the North Indian Ocean—the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the Joint Typhoon Warning Center (JTWC) releases unofficial advisories. An average of five tropical cyclones form in the North Indian Ocean every season with peaks in May and November. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.

The 1993 North Indian Ocean cyclone season was the quietest on record in the basin, with only four tropical disturbances. There are two main seas in the North Indian Ocean – the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west. The India Meteorological Department (IMD) issued advisories for the systems in its official capacity as the local Regional Specialized Meteorological Center, while the Joint Typhoon Warning Center also issued advisories for two of the storms on an unofficial basis. Of the five disturbances tracked by the IMD, two intensified into cyclonic storms.

The 1985 North Indian Ocean cyclone season was part of the annual cycle of tropical cyclone formation. The season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. There are two main seas in the North Indian Ocean—the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the Joint Typhoon Warning Center (JTWC) releases unofficial advisories. An average of five tropical cyclones form in the North Indian Ocean every season with peaks in May and November. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.

The 1987 North Indian Ocean cyclone season was part of the annual cycle of tropical cyclone formation. The season has no official bounds but cyclones tend to form between April and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. There are two main seas in the North Indian Ocean—the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west of India. The official Regional Specialized Meteorological Centre in this basin is the India Meteorological Department (IMD), while the Joint Typhoon Warning Center (JTWC) releases unofficial advisories. An average of five tropical cyclones form in the North Indian Ocean every season with peaks in May and November. Cyclones occurring between the meridians 45°E and 100°E are included in the season by the IMD.

The 2009 North Indian Ocean cyclone season was an event in the annual cycle of tropical cyclone formation. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.

The 2014 North Indian Ocean cyclone season was an event in the annual cycle of tropical cyclone formation. The season included two very severe cyclonic storms, both in October, and one other named cyclonic storm, classified according to the tropical cyclone intensity scale of the India Meteorological Department. Cyclone Hudhud is estimated to have caused US$3.58 billion in damage across eastern India, and more than 120 deaths.

The 2016 North Indian Ocean cyclone season was an event in the annual cycle of tropical cyclone formation. It was the deadliest season since 2010, killing more than 400 people. The season was an average one, seeing four named storms, with one further intensifying into a very severe cyclonic storm. The first named storm, Roanu, developed on 19 May while the season's last named storm, Vardah, dissipated on 18 December. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with the two peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.

The 2017 North Indian Ocean cyclone season was a below average season in the annual cycle of tropical cyclone formation. This season produced only three named storms, of which one only intensified into a very severe cyclonic storm. The North Indian Ocean cyclone season has no official bounds but cyclones tend to form between April and December with the two peaks in May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. The season began with the formation Cyclone Maarutha on April 15 and ended with the dissipation of a deep depression on December 9.

The 2019 North Indian Ocean cyclone season was the most active North Indian Ocean cyclone season ever recorded, featuring 12 depressions, 11 deep depressions, 8 cyclonic storms, a record 6 severe cyclonic storms, a record 6 very severe cyclonic storms, a record 3 extremely severe cyclonic storms, and 1 super cyclonic storm, Kyarr, the first since Cyclone Gonu in 2007. Additionally, it was also the second-costliest season recorded in the North Indian Ocean, only behind the 2020 and 2008 seasons.

The 2020 North Indian Ocean cyclone season is an ongoing event in the annual cycle of tropical cyclone formation. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and November, with peaks in May and October. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean. The season began on May 16 with the designation of Depression BOB 01 in the Bay of Bengal, later to become Super Cyclonic Storm Amphan, one of the strongest storms in the bay recorded and the costliest storm on record in the basin.